Merge branch 'fixes' of https://git.kernel.org/pub/scm/linux/kernel/git/vkoul/dmaengine.git

1 files changed, 16 insertions, 5 deletions

diff --git a/include/linux/dma/qcom_bam_dma.h b/include/linux/dma/qcom_bam_dma.h
index 68fc0e643b1b..d9d07a9ab313 100644
--- a/include/linux/dma/qcom_bam_dma.h
+++ b/include/linux/dma/qcom_bam_dma.h
@@ -13,9 +13,12 @@
  * supported by BAM DMA Engine.
  *
  * @cmd_and_addr - upper 8 bits command and lower 24 bits register address.
- * @data - for write command: content to be written into peripheral register.
- *	   for read command: dest addr to write peripheral register value.
- * @mask - register mask.
+ * @data - For write command: content to be written into peripheral register.
+ *	   For read command: lower 32 bits of destination address.
+ * @mask - For write command: register write mask.
+ *	   For read command on BAM v1.6.0+: upper 4 bits of destination address.
+ *	   For read command on BAM < v1.6.0: ignored by hardware.
+ *	   Setting to 0 ensures 32-bit addressing compatibility.
  * @reserved - for future usage.
  *
  */
@@ -42,6 +45,10 @@ enum bam_command_type {
  * @addr: target address
  * @cmd: BAM command
  * @data: actual data for write and dest addr for read in le32
+ *
+ * For BAM v1.6.0+, the mask field behavior depends on command type:
+ * - Write commands: mask = write mask (typically 0xffffffff)
+ * - Read commands: mask = upper 4 bits of destination address (0 for 32-bit)
  */
 static inline void
 bam_prep_ce_le32(struct bam_cmd_element *bam_ce, u32 addr,
@@ -50,7 +57,11 @@ bam_prep_ce_le32(struct bam_cmd_element *bam_ce, u32 addr,
 	bam_ce->cmd_and_addr =
 		cpu_to_le32((addr & 0xffffff) | ((cmd & 0xff) << 24));
 	bam_ce->data = data;
-	bam_ce->mask = cpu_to_le32(0xffffffff);
+	if (cmd == BAM_READ_COMMAND)
+		bam_ce->mask = cpu_to_le32(0x0); /* 32-bit addressing */
+	else
+		bam_ce->mask = cpu_to_le32(0xffffffff); /* Write mask */
+	bam_ce->reserved = 0;
 }
 
 /*
@@ -60,7 +71,7 @@ bam_prep_ce_le32(struct bam_cmd_element *bam_ce, u32 addr,
  * @bam_ce: BAM command element
  * @addr: target address
  * @cmd: BAM command
- * @data: actual data for write and dest addr for read
+ * @data: actual data for write and destination address for read
  */
 static inline void
 bam_prep_ce(struct bam_cmd_element *bam_ce, u32 addr,